1. Technical Field
The invention relates to a numerical control method based on a “cloud calculation” mode and parallel processing of discrete network, belongs to fields of numerical control system, parallel information processing, network technology and industrial control, particularly related to numerical control machining, cooperative manufacture management, parallel control, remote measurement and control, troubleshooting treatment, communication network, automatic control and signal processing.
2. Related Art
The first generation of numerical control systems was established in 1952 with evacuated tubes. After that, the second generation was based on transistors, the third generation was based on integrated circuits, the fourth generation was based on small computers and the fifth generation was based on microcomputers. Currently, the sixth generation of numerical control systems is based on personal computers (PC). The PC numerical control is the most important improvement since the numerical control technology was established. In comparison with the fifth generation, the hardware platform and software platform of the PC numerical control are completely general. Although the fifth generation of numerical control systems is also known as “computer numerical control system”, computers in such a system are of a proprietary type which must be developed and produced by the manufacturers of numerical control systems. Not only must the hardware systems be produced by the manufacturers of numerical control systems, but also fundamental software systems such as an operating system must be developed according to the hardware systems. Because the manufacturers of numerical control systems are not very skilled in development and production of computers, many problems occur, for example, the development period is too long, upgrade is too slow, performance is not good enough and manufacturing costs are too high. The sixth generation of numerical control systems based on general PCs completely overcomes those drawbacks so as to make the computer numerical control technology become faster and more reliable. A primary object of previous numerical control systems is motion control. Mainly controlled objects are electrical driving systems with multiple motion axles and a spindle. By the means of accepting commands of machining program design, simple or complicated motion control can be implemented so that numerical control machining is implemented, too.
In recent years, because the requirements of advanced manufacturing process keep higher and higher, pure motion control cannot satisfy the more complicated and accurate requirements of production. Such requirements of production include three aspects as follows:
a) A numerical control system must not only performs control and management of machining devices, but also be the online participates with management and cooperation in a company and between companies. Furthermore, a numerical control system must satisfy the integration requirement of CAD/CAPP/CAM functions. All of those requirements push the numerical control system to have stronger abilities of data processing, real-time control, discrete measurement and control, communication processing and parallel processing;
b) With higher and higher complicacy of numerical control machine-tools and other numerical machining devices, mere motion control is not enough, and more functional requirements are submitted, for example, various advanced combinative control functions in a complicated machining process (control and compensation functions of temperature, vibration, stress, tension and deformation), online automatic compensation function of abrasion of a cutter in a cutting process, online temperature compensation function of a machine-tools, online detection of various parameters of workpieces, complex machining combinative control function (such as drilling, grinding, scrolling and pressing), online simulation and verification of complicated machining, online monitor and troubleshooting treatment of numerical control machine-tools, online upgrade and technical support of numerical control systems, and so on;
c) With development of advanced manufacturing technology, from computer integrated manufacturing system to cooperative manufacturing systems between multiple companies, further to the “cloud manufacturing” provided in recent two years, all of those request numerical control systems to possess higher performance, i.e., a requirement of flexible cooperative manufacturing. Such a requirement of flexible cooperative manufacture pushes a numerical control machining device to be more intelligent.
To accomplish the above requirements, a numerical control system must have multiple functions of various motion control in a single device, combinative control, complex control, integration of CAD/CAPP/CAM, and cooperative control and match control with other devices.